Toggle



June 23, 1942. P DE MATTlA l 2,287,417

TOGGLE Filed Feb. l1, 1941 2 Sheets-Sheet 1 ,l Mrllml n f Q Wf Num A H35 /g Ue wk QR I6 /5 ZZ Z55/Z BY 57 55 54 s@ j MTM Juxne 23, 1942. P. DEMATTIA` '2,287,417

ToGGLE Filled Feb. 11, 1941 2 sheets-sheet 2 Patented June 23, 1942UNITED STATES ATE-NT OFFICE TOGGLE `Peter De Mattia, Passaic, N. J .Y

Application February 11, 1941, SeriaLNo. 3718.388 22 Claims. (Cl.74-10(i') This invention .relates to toggles and similar devices.

One object ofthe invention is to provide a device comprising a plurality'of links Vconstructed in an Aimproved manner for direct pivotalabutment between `the elinks to zavoid yshearing strain on gpins,especially in or near dead center position.

Another object of the invention is to provide a -devi'ce comprisingspaced relatively movable members, and means vcomprising linksinterengaged for direct abutment with each yother and with at leastoneof the members in an improved manner vto avoid vpin shearingstresses.

Another object of the invention is -to furnish a device as set forthvhavin-g improved .means for direct abutment 'along surfaces yrolling`on each other in course of pivotal movement.

Another object `of ythe invention is the provisionof a devicecomprising-a'toggle @having a pivotalzlink arranged or constructed `inanimproved manner to exert an abuttingpressure throughout a plane,surface .area for'maximum ,resistance against a compression load.

Another object of the invention -is -to ,turnishi a device as referredito .having :improved ,pvotally `interengaged elements v directlyabutting in rolling interengagement. coaxially with connecting bearingsin which the pivotal movement tis limited, wherebythe'devce is easilyzcontrolled :if: l

lone of the elements :has a temporarily `free end.

lAnother 'object -of -the invention is to provide a device -including alinkage one end of which vis desirably connected -to a movable memberand the other endof which fis :movable into :and out of engagement ,with-a fixed member, at vleast part of the linkage-being loperable l.toinitially move the movable member andthe linkage being 1then Yengagedwith the fixed member for Afinal :movement -of the -linkage to deadcenter position,

Vwhereby compactness is increased, and-'the wrange of lmovement 'of theVmovable member is increased, and Ifewer .bearings are required, and asimplied actuator means lis 'available for utilizing `part vof thelin-ka'geto y'cause the said initial arrangements of parts hereinafterdescribed in their preferred embodiments, pointed out in the subjoinedclaims, and illustrated in the annexed drawings, wherein like `parts.are .designated by the `same reference characters throughout .theseveral views.

-In the drawings:

Figure v1 is .a .diagrammatic sectional View' .showing a dev ice.embodying the invention.

Fig. 2 is an isometric view o'f alink embodying the invention.

Fig. 3 -is a diagrammatic .view with parts in section showing .amodcaton of the -invention With a linkage in dead .Qenterposition Fig. 4is a similar view thereof but. ,sl1o. wingfthe linkage y of Rig. 3 ,inopen or collapsed position.

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 3.

Fig. 6 is a fragmentary .diagrammatic view showing a modification tin.dead .Center POSiOn Fig. -7 is a similar vView of still a )urthermodification in yopen position.

Fig. 8 .is a fragmentary plan v iewshowing the preferred vform vof .theinvention as .applied to a molding vmachine or the like.

The advantages of the invention as here outlined are best realized when,allof its features and linstrumentalities are Combined in one `and thesame structure, but, useful devices may be lproduced embodying less thanthe whole.

It will be obviousto those skilled'in the art to which the inventionappertains that the same may be incorporated in several differentconstructions. The accompanying drawings, therefore, are submittedmerely as showing the preferred exemplirlcation of -the invention.

Referring in detail tothe drawings, I0 denotes a device embodying 'theinvention. The same may include relatively 'fixed and movable members IIand `I2 respectively, the member I2 being movable in a straight path,and vany -motor I3 movable parallel to said-path'and being adapted tocause'reciprocation of `fthe Vmember "I2, For transmitting powerfromt-he motor to -the lmember I2, la toggle I4 'is provided, which mayinclude links 1I5that may be iidentical with each other.

As shown inFig. 2, -eachmember I5 may-consist of a plane plate fofuniform thickness and being of the shape of arectanglaexceptsthat it may`have segmental shafts I6 vand I'I integrally projecting therefrom. Each:olffsaid shafts is kin cross section less than a --semiirc1 e,;andeach-is bounded by a section ora-cylindrical surface at I S, thediameteriof vwhich is substantially fequal to the thickness of theplate. The opposite or outer sides of each segmental shaft I6 and I1 isformed by two plane surfaces I9, 20 forming an obtuse angle with eachother. The surfaces I9 constitute the normal edge surfaces of the plateI and are at right angles to the plane thereof, and may extendcontinuously along the segmental shafts. The surfaces are parallel toeach other, and also form continuous surfaces along the 'ends of the`link and along the segmental shafts I 6, I1. Both surfaces I9 and 20are radial to the axis of their segmental shafts,

and thus the areas of both are substantially.

equal.

It will thus be apparent that the segmental shafts I6, I1 are actuallyduplicates of each other, except that in angular relation, one is at 180degrees relative to the other. It will be further perceived that theplane surfaces I9, 2i)Y at an end of the link may be considered asforming a generally convex surface; in fact, they may be replaced by asegment of a cylindrical surface except that the abutting pressure indead center position would be Yalong a line of tangency, instead ofalong the large area afforded by a plane surface. The latter possessesthe advantage of maximum distribution of bearing pressure and is thusless subject to distortion and wear than a curved surface. Within thescope of the invention, the term convex surface denotes both. Infact,the surfaces I9, 20 are curved along their line of intersection 2| toreduce wear and distortion; such curvesare also afforded atsimilar'intersecting surfaces of the other modifications herein.

When two links I5 are placed end to end, as in Fig. 1, adjoiningsegmental shafts I6 and I1 form in effect a single shaft or pin Whichmay be received in a circular collar or bearing such as 22 so that thecylindrical faces I8 are in contact with the cylindrical faces of thebearing. But due to the angularity of the surfaces I9 and 20, freeradial spaces, such as sectors of a circle result which afford clearancefor a relative angular movement of the shafts I6, I1 and hence of thelinks I5.

Any suitable bearing elements such as the yokes or collars 23 may securethe different segmental shafts I6, I1 to the members II and I2'.Desirably the adjacent faces 24 of these members are plane for abuttingcontact with the surfaces I9 when vthe linkage is in dead centerposition as shown in Fig. 1. In that sense the members II and I2, or atleast their surface portions such as 24 are herein considered as partsof the bearings, and the term bearing as here used is intended also toapply in the modifications hereinafter described.

To actuate the linkage I4, a link 25, of which the bearing element 22may be a part, may be connected to the motor I3 at a Suitable angle.

In operation, when the motor or cross head I3 moves to the right, thelink 25 pulls downward on the linkage I4, collapsing the same andpulling the member I2 rightward. Downward movement of the linkage islimited by abutment of the facesv at 24, and by abutment of the adjacentfaces 2U with each other. While such stop action is desirable, it is notabsolutely essential, since the device I3 may aiford a stop. But it isessential to cut away as little metal as possible especially at theshafts I 6, I1 and hence in a carefully designed device, the faces "20Will move to the limit of movement. 'Ihis observation applies to all theforms of the in vention herein disclosed.

Further considering the operation, when the device I3 moves leftward,the link 25 pushesthe linkage I4 upward and toward the left, causing aleftward movement of the member I2 and moving the linkage I4 to the deadcenter position shown in Fig. 1. As this movement proceeds, the surfacesI 6, I1 roll on adjacent surfaces in the same way as if they werecircular. 'Ihus such rolling occurs on the surfaces 24 and on theadjacent surfaces I6 and I1. In other words, there is no sliding motion,hence no friction. There are no pins to shear. In dead center position,extreme power is attained, and actually the linkage I4 forms a verypowerful column which is capable of exerting many hundreds of tonsof-'compressive force, although the stress per square inch is relativelylow. This feature is of substantial importance in presses and moldingmachines, in which wear, and abrasion rapidly occurred. To withstand theextreme stresses, the toggles used were of hardened steel and hencesubject to fracture under shock.

It is thus an important advantage of the invention that the links suchas I5 may be made of a low grade steel, suitably carburized to form astrong hard surface portion with a tough softer interior to take theshock. y

It is important to note that while the surfaces I9 and 20 may haverolling abutting engagement within the different bearings, this is notreally essential, and it is sufficient that the segmental shafts I6, I1act as pivotal connectors. The body or link proper affords sufficientabutment area for all necessary purposes. Hence the surfaces I9, 20 maybe spaced out of abutment within the different bearing elements, butease of manufacture calls for uniform continuous surfaces I9 and 20throughout. These observations apply also to the other forms of theinvention.

In Figs. 3, 4 and 5 is shown a modied form ofthe invention whichrepresents the preferred embodiment, being the one which I have-foundbest suited in actual use in a molding machine; Whereas the device IIJserves as a simplified illustration of the invention. In the device 26are spaced relatively `movable members of which 21 may be fixed and 28movable. Interengaging these is a linkage 29 comprising the link I5 anda link 30. 'Ihe latter differs from the link I5 only in its physicaldimensions and in the fact that it is in only temporary engagement withthe member 21,'having a flat, free end portion or heel 3| engageable ina recess 32 of the member 21. Because the linkage is not connected tothe member 21, it is normally inclined at an angle in its dead centerposition as shown, so that the link portion 3| is'laterally forced intothe recess 32 and cannot slip therein. In consequence, the surface 24 ofthe device I0 is modified to provide a surface 24a terminating at thecenter of the bearing 23, and a surface 24h which is recessed into themember 28 to lie at an angle so as to be at right angles to the linkagewhen the latter is in its dead center position. Instead of the element25 of the device I0, a crank-like member 33 is provided which mayinclude the bearing 22 as a part thereof. Extending through the link 30and the members 33 which are at both sides of the toggle is a lpin 34,which engages the links 35 that are pinned at 36 to a head 31 that movesin parallel relation to the path of the member 28. To facilitate outwardmovement of the link 30, an arm '38 rigid on the member 31 may have camor wiping engagement with the link 30 as 'oper-ating with this-link 401is av recessed portion thelmember 31Jmoves leitward.

In'operation, Fig. 4'- inV plan View shows the device 26 collapsedwith-the member 29 retracted toward the right. In the bearing 23, thesurfaces 20 and 24o. are inabutment; in the bearing 22, the surfaces 2U?are in abutment. The-link 30 is inclined outward with its end portionbeyond the recess-32 andinside or beyond the adjacent part of the member21. Thus it isv seen that the spacingbetween the members 21 and 28 maybe-reduced-to be less than the length of the toggle 29 when collapsed.The element 30 is desirably in wiping ory sliding contact with theinside-face of the member- 21l which thus serves as a guide for the freeend of this element 3D'. An important feature of the invention is thatthe seat at 32' is laterally outward or beyond the bearing at 23, withthe toggle of Fig. 3 being at an angle as shown.

Due to the angle of' the element 35, when the member 31` moves towardthe left, it causes a leftward travel of the member 28, the free end ofthe element 3| sli-ding along the member 21. The member 28 initiallyoffers little resistance, and the inward break in the toggle at thebearing 22, with the application of power at the pin 34 permits thismovement to occur. As the heel 3| moves into line with the recess 32,the resistance of the member 28 may be considered to have increased, andhence the toggle may begin to straighten out; or if the resistance ofthe member k28 is still low, the latter may be moved to its end positionat the left substantially as in Fig. l, and then the toggle maystraighten out. As the member 31 continues its movement toward the left,the arm 38 assures that the-link 39 moves outward sufliciently to befully received in the recess 32. Then the toggle attains its dead endposition as in Fig. l. It need not be moved past `dead end position,because the flat bearing surfaces assure a reliable locking irrespectiveof the members 35 and 31. The member 39 may be omitted if preferred.

In the dead center position, the surface 20emgages surface 24h, andsurfaces 20 engage in the bearing 22, and the heel engages the wall ofthe recess 32. All these provide large abutment areas that aresubstantially in alinement with each other.

The importance of the inclined or angular position of the toggle 29 whenin dead center position as in Fig. 3 will now be apparent; in fact, ifthe toggle were parallel to the path of the actuator 31, the operationwould-not be satisfactory. This is believed to be more clearly apparentby reference to Fig. 8, which is like the devices of Figs. 3 and fl,except that it shows two toggles according to an actual installation,When the actuator 31v moves to the right, the angularity of the straighttoggles assures an accentuated force tending to break the toggles, andassures that the break occurs before the free end portion 3| of the link3D is caused to leave its recess 32, and no binding occurs. In fact, theprincipal reason for providing the free end portion 3l is to realize ina high degree the advantage of the angularity of the straight toggle.When the actuator 31 moves toward the left, there is facilitated themovement of the member 28, then the engagement of the link 30`in therecess 32 and iinally the straightening of the toggle.

In Fig. 6 is shown a modiied device 39 which is intended to illustratethat one of the links such as 40 may be free of the inclined faces 29.

lli in the movable member 42. Thesecond link 43'may be likethe linkt 30,but the inclined face Zllthereoff mayY be at al larger angle thanbefore. The-segmental shaft l-Sthereof isin rolling abutment withtheplane right angle end face 44 of the link49; and the like face 49' atthe other end of' the link isv in rolling abutting engagement with theface ofthe member 42 including the recess 4| thereof. The device 39 mayinclude the actuator means of the device 26.

In Fig. '1Y is showna modied device 95 to illustra-te that no connectingbearings are needed at either the fixed` nor movable members 46, 41.These may be provided'with like stepped formations 43, and thelinks 49may be duplicates of each other, each having segmental shafts 50 likethose at l5 engagedin bearings 22 of the actuator 25. The plane rightangle end faces 5| have rolling abutting engagement with the steppedformations-@las indicated in-the device 39. Retraction of the-movablemember 41 may be caused by a tensionl spring 52 or other actuator. Thelinkage actuator may serve to support the linkage-when the latteriscollapsed as shown. In Figs. 6 and 7, the surfaces at 4l and 48Vafford convex abutting faces.

I cla-im:

1'. A device including a relatively fixed first member, a reciprocableysecond member for delivering a power stroke, a toggle whereof one linkis connected to the secondmember and the other link is separablyengageable with the first member, actuator means for expanding and co1-lapsing the toggle and for reciprocating the toggle to an extent lessthan the path ofmovernent ofv the secondl member, the separable linkbeing adapted to move laterally away from the first member in thecollapsing position of the toggle, said actuator means causing saidlateral movement of the separable link and causing the connected link toretract: the second member, the actuator means causing the connectedlink to initially advance the second member and moving the separablelinkinto engagement with the rst memberQ and nally causing the toggle tomovesubstantially to dead center position, and stop means for limitingthe lateral movement ofthe separablelink to cause the toggle to assume apredetermined expanding position.

2. A device including a relatively fixed first member, a reciprocablesecond member for delivering a power stroke, a toggle whereof one linkis connected tothe second member and the other link is separablyengageable with the first member, actuatormeans for expanding andcollapsingA the toggle and for reciprocating the toggle to an extentless than the path of movement of the second member, the separable linkbeing adapted to moven laterally away from the nrst memberv in thecollapsing position of the toggle, said' actuator means causing saidlateral movement of the separable link and causing the connected link toretract the second member, the actuatormeans causingthe connected linkto initially advance the second member and moving the separable linkvinto engagement with the rst member and iinally causing the toggle tomove substantially to deadv center position, and stop means for limitingthe lateral movement of the separable link. to cause the toggle toassume apredetermined expanding. position, said toggle when in deadcenter position lying Yat an angle to the path of the second member sothat the separable link laterallyv abuts the stop means.

3. In a toggle link mechanism, the combination of two spaced relativelymovable members, and a linkage adapted to interengage said members,comprising a pair of links, and a bearing means interconnecting the samecomprising a pair of fragmentary shafts which extend along each otherand are adapted for relative angular movement about the axis of thebearing means, each of said shafts affording a fragment of a cylindricalsurface and each being nonrotatably connected to its respective link,and a cylindrical collar engaging around said shafts in engagement withboth of said fragmentary cylindrical surfaces, and at least one of saidlinks having another like fragmentary shaft directly pivotallyabuttingone of said members.

4. A device including a relatively fixed first member, a reciprocabl'esecond member for delivering a power stroke, a toggle whereof one linkis connected to the second member and the other link is separablyengageable with the first member, actuator means for expanding andcollapsing the toggle and for reciprocating the toggle to an extent lessthan the path of movement of the second member, the separable link beingadapted to move laterally away from the iirst member in the collapsingposition of the toggle, said actuator means causing said lateralmovement of the separable link and causing the connected link to retractthe second member, the actuator means causing the connected link toinitially advance the second member and moving the separable link intoengagement with the first member and finally causing th'e toggle to movesubstantially to dead center position, and stop means for limiting thelateral movement of the separable link to cause the toggle to assume apredetermined expanding position, said actuator means including a powerelement reciprocable in generally parallel relation to the secondmember, a link connecting the power element to the toggle for operatingthe latter, and an arm on the power element for releasably engaging theseparable link as the second member is being advanced to laterally movethe separable link into engagement with the stop means.

5. In a toggle mechanism, the combination of two spaced relativelymovable members, and a linkage interengaging said members and adapted topowerfully move the same apart in the dead center position of thelinkage, a first bearing means interengaging the links of the linkage, asecond bearing means engaging one of the links with a first of saidmembers, at least one bearing means comprising shaft portions adaptedfor rolling engagement with each other, the said links having portionshaving direct rolling engagement with each other about the axis of thefirst bearing means, the link at the second bearing means having aportion having direct rolling engagement with said member about the axisof the second bearing means, said axes being transverse to said links,the link having engagement with the second of said members being movableinto and out of engagement therewith, and actuator means connected tothe last mentioned link for moving the latter into and out of saidengagement and for thus causing expansion and collapse of the linkage.

6, A device including a relatively fixed first member, a reciprocablesecond member for delivering a power stroke, a toggle whereof one linkis connected to the second member and the other link is separablyengageable with the first member, actuator means for expanding andcollapsing the toggle and for reciprocating the toggle to an extent lessthan the path of movement of the second member, the separable link beingadapted to move laterally away from the first member in the collapsingposition of the toggle, said actuator means causing said lateralmovement of th'e separable link and causing the connected link toretract the second member, the actuator means causing the connected linkto initially advance the second member and moving the separable linkinto engagement with the first member and finally causing the toggle tomove substantially to dead center position, and stop means for limitingthe lateral movement of the separable link to cause the toggle to assumea predetermined expanding position, and means operated by the actuatormeans for releasably engaging the separable link for moving the sameinto engagement with the stop means.

7. A device including a iirst member movable along a path, mechanismcomprising a toggle linkage comprising a plurality of links pivotallyinterconnected, one of said links being connected to the first member,the second link being movable into and out of engagement with the secondmember, and actuator means movable along a path parallel to that of thefirst member, comprising a link element connected to the second link ata point intermediate of the axis of pivotal connection and the secondmember. said actuator means being movable to cause the link element topull on the linkage to break the toggle and to retract the first member,said mechanism including means to limit the breaking movement of thetoggle linkage, `and the actuator means being movable in an oppositedirection to cause the link element to move the linkage for causing aforward movement of the first member and a swinging movement of thetoggle linkage with the second link being moved into engagement with thesecond member and the toggle linkage being finally moved to dead centerposition by said link element under continued movement of the actuatormeans.

8. A device according to claim "I, wherein said actuator means includesa cam means for engaging the second link to urge the same intoengagement with the second member in course of movement of the actuatormeans.

9. A device according to claim 7, wherein the toggle linkage in its deadcenter position extends at an angle to the path of travel of the firstmember, the second member having a recess for engaging and retaining theend of the second link in the dead center position.

10. A device including a toggle means comprising a toggle linkconsisting of a plate having at one end a surface convexed in adirection transverse to the thickness of the plate, said plate havingside projections having convex surfaces forming straight continuationsof the convex surface of the plate, said projections constitutingfragmentary shafts Whose common axis lies along the center line of theconvex surfaces.

ll. A device including a toggle means comprising a toggle linkconsisting of a plate having at one end a surface convexed in adirection transverse to the thickness of the plate, said plate havingside .projections having convex surfaces forming straight continuationsof the convex surface of the plate, said projections constitutingfragmentary shafts Whose common axis lies along the center line of theconvex surfaces, means having fragmentary shafts substantiallycomplemental to those first mentioned, but one set of the shafts beingcross-se-ctionally less than the other vso that said fragmentary shaftsare adapted' for pivotal movement 'relative to veach other, and 'bearingelements interconnecting vthe adjacent shafts.

f12. A device including power means comprising a `relatively xed rstmember, a reciprocable .second power member, a toggle whereof onelink'is connected to .the second member and .the second linkseparablyengageable with the first member, .said .toggle being vmovablesubstantial- 1y to dead center position between the members for movingsaid members .apartsaid toggle'being collapsible with the separable linkmovable clownward for partially underlying the first member, the powermeans having means for limiting the angular movement of .the toggle, a:power felement reciprocable in a path extending vin the generaldirection of reciprocation of the :second member, and actuator meansoperated bythe power element for operating the toggle and `incooperation with said limiting means, for recip rocating the toggle .toan Aextent less than the path of Vmovement of the second member whilemoving the second link upward and downward according to the dead centerand collapsed bosition of the toggle, the lactuator means :thus causingthe second member to move away from the rst member vto make room for theseparable link whereby the toggle is engaged between vthe members forthe power stroke of the second member.

13. -A device including a ,power means comprising a relatively fixedfirst member, a reeiprocable second power member, a toggle whereof onelink Vis connect-ed tothe second member and the second link separablyengageable with the first member, said toggle being movable substamtially to dead center .position between the memn bers for moving saidmembers apart, said toggle being collapsible with the separable link movable downward for partially underlying the first member, the power meanshaving means for limiting the angular movement of the toggle, a powerelement reciprocable in a path extending in the gener-al direction ofreciprocation of the second member, and actuator means operated by thepower element for operating the toggle and in cooperation with saidlimiting means, reciprocating the toggle to an extent less than the pathof movement of the second member while moving the second link upward anddownward according to the dead center and collapsed posiftion of thetoggle, the actuator means thus causn1 ing the second member to moveaway from the rst member to make room for the separable link whereby thetoggle is engaged between 4the members for the power stroke of thesecond member, said actuator means including a link interconnecting thepower element with the sep-- arable link at a point intermediate of theends of the latter, with the link of the actuator means being generallyparallel to the connected link of the toggle in the collapsed positionof the lat ter, and the toggle cooperating with the actuan tor means andthe power element to limit the collapsing position of the toggle forobtaining said generally parallel position.

14. A device including a mechanism comprising a plurality of spacedrelatively movable members, and a toggle therebetween comprisingpivotally interengaged link members adapted for pivotal engagement withthe adjacent respective relatively movable members, all of said membershaving interengaging means for pivotal rolling engagement between thetoggle and at least one of the relatively movable members, andbetweenthe `linkmembers, each of said means :comprising a convexsurfaoefportion on one `member c0- operating in direct abutment with asurface p0rtion on an adjacent member "for rolling onithe convex surfacel.portion in lcourse of operation of the toggle, each .convex surface`portion comprising surfaces atan obtuse angle to .ea-.ch other,certainof said :surfaces V.being plane and being so locatedas to takethe'dlrect-abutment'pressure when the toggle is in dead center position.15. Adevice including a `relatively fixed first member, a reciprocablesecondmemberl'for delivering a power stroke, --a-toggle whereof `onelink is connected Ato the A-secondmember and vthe other link isseparably engageable with the -rst-member, actuator means for expandingand collapsing the toggle `and `for reciprocating the toggle to Ianextent less than the Apath 'of movement of the second member, theseparable link :being adapted to Ymove laterally away from the flrstmember in the collapsing position of the toggle, said actuator-meanscausing said lateral movement of the separable link and causingthe connected link vto retract the second member, the actuator meanscausing the connected link to initially advance the -secondmember andmoving the separable link into engagement withthe first member and nallycausing the toggle to move substantially to dead center position, andstop means for limiting the lateral movement Of Lthe separable link tocausetlie toggle :to assume a predetermined expanding position, theconnected link and the second member having engagement means and thelinks having like engagement means therebetween, Said engagement' meanshaving angularly related relatively rplane abutment surface portionsproviding at least one convex surface for flatwise abutment at one oranother of the surface portions according as the toggle is in deadcenter or collapsed position.

16. A device according to claim l5 wherein the connected link hasfragmentary shafts at its opposite ends and the separable link has likefragmentary shafts at its adjacent end, said surface portions beingextended along said fragmentary shafts, and bearings for the fragmentaryshafts including a substantially half circle bearing connecting theconected link to the second member and a full circle bearinginterengaging adjacent shafts of the links.

17. A device including a plurality of members movable relatively to eachother, means for caus ing said relative movement comprising a toggle,and means for actuating the toggle, said means having bearing means,including angularly related relatively plane abutment surface portionsproviding at least one convex surface, for flatwise abutment at onesurface portion with other surface portions being angularly spaced fromeach other in an expanded position of the toggle, whereby non-rollingabutting engagement is obtained in course of movement of the toggle.

18. A device including a plurality of members movable relatively toeachother, a first means for causing said relative movement comprising atoggle, and means for actuating the toggle, said first means havingbearing means, including angularly related relatively plane abutmentsurface portions providing at least one convex surface, for flatwiseabutment at one surface portion with other surface portions beingangularly spaced from each other in an expanded position of the toggle,whereby non-rolling abutting engagement is obtained in course ofmovement of the toggle, and at least one fragmentary shaft forming anextension of at least one of said surface portions, and a bearingengaging around said shaft.

19. A device including a plurality of relatively movable head membersand a toggle operatively associated with said members including aplurality of link members, one of said members having relatively planesurface portions at an angle to each other to define a convex abutmentsurface, and an adjacent member having an abutment vsurface portioncooperating therewith so that as the toggle is expanded or collapsed oneor another of the relatively plane surface portions comes intoengagement with said cooperating surface portion for a non-rollingabutting contact.

20. A devicefincluding a plurality of relatively movable head membersand a toggle operatively associated with said members including aplurality of link members, one of said members'having relatively planesurface portions at an angle to each other to dene a convex abutmentsurface, and an adjacent member having an abutment surface portioncooperating therewith so that as the toggle is expanded or collapsed oneor another of the relatively plane surface portions comes intoengagement with said cooperating surface, and a fragmentary shaft on oneof the members having one face portion forming an extension of theabutment surface of said member, and a bearing for said shaft mounted onthe adjacent member.

21. A device including a plurality of relatively movable head members,and a toggle operatively associated therewith, including a plurality oflink members, one of the latter having a fragmentary shaft not greaterthan a semicircle in cross section, a bearing receiving and connectingsaid shaft to an adjoining member, the latter lhaving a surface portionin fixed relation thereto and cooperating with the bearing for coactionwith the shaft, the shaft having a surface portion in fixed relationthereto and within the bearing adapted to directly abut the firstmentioned surface portion in a substantially dead center position of thetoggle, at least one of said surface portions having a convex abutmentsurface confronting and constantly contacting the other surface portionso that different parts of the convex surface become subject to abutmentpressure as movement of the toggle progresses, whereby the abutmentpressure is transmitted by generally rolling contact, as distinguishedfrom sliding contact, directly between the said surface portions.

22. A device including a plurality of relatively movable head membersand a toggle operatively associated with said members including aplurality of link members, one of said members having a convex surfaceportion, and an adjacent member having an abutment surface portioncooperating therewith so that as the toggle is expanded or collapsed theconvex surface portion contacts the abutment surface portion atdiiferent successive points for a rolling engagement about an axis, acoaxial fragmentary shaft on one of said members having one face portionforming an extension of the surface portion of said member, the othermember having a surface portion cooperating with the surface portion ofthe fragmentary shaft to permit angular movement thereof, and a bearingextending around the fragmentary shaft for interconnecting the adjacentmembers.

' PETER DE MATTIA.

